Author Topic: Limb twist  (Read 894 times)

Offline AKmud

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Limb twist
« on: March 21, 2009, 03:34:00 AM »
What is the best way to fix a slight limb twist in a board bow?  I have a hickory bow that I am working on and it lays completely flat when unstrung, but when I string it, one limb starts to twist slightly to one side.  I have experimented with taking belly material off the outside and then the inside of the twist, but I can't see any real changes from either side.  I don't want to take too much off since I am already at my target weight and the tillering looks really good at 28" other than the twist...

Any simple solutions?

Offline George Tsoukalas

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Re: Limb twist
« Reply #1 on: March 21, 2009, 08:47:00 AM »
The twist in your case was caused by uneven wood removal. To is it even the wood removal. Staves twist towards the weak side so remove wood from the other side.  The weak side is the side closest to the string in the strung bow. Often we favor one side of both limbs in wood removal so the stave twists. Get in the habit of at least a visual inspection or an inspection by feel to assess the evenness of the removal. If it isn't too bad and you have had it to your draw yo may decide to leave it. Jawge

Online Pat B

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Re: Limb twist
« Reply #2 on: March 21, 2009, 08:55:00 AM »
Proper tiller should be your first goal then achieving weight, next. Without proper tiller it doesn't matter what weight you end up with. If your bow lays flat unbraced but has a twist when braced the limb thickness, from one side to the other side is probably different. Remove wood from the thicker side, exercise the limbs after each wood removal and check it again to see if the twist is gone.
   I try to get my limbs bending evenly and together at floor tiller or at least before 10" of tip movement. By doing so, I can concentrate on good limb bends as I tiller plus achieving the desired weight.
Make the most of all that comes and the least of all that goes!
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Offline AKmud

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Re: Limb twist
« Reply #3 on: March 21, 2009, 12:22:00 PM »
Thanks guys, I'm guessing I tend to always work the wood from one side of my vise which probably adds to the uneven wood removal.  I'll have to get in the habit of working from both sides more often.  

I worked with the bow quite a while last night and finally got about 90% of the twist taken care of and piked the bow to get my weight back up over 50#.  I put about 10-15 arrows through it last night and it performed well.  

I kept looking from the tip and examined that twist and for the life of me I couldn't figure out which side needed to be worked!  I thought I had the limb thickness pretty even, but I guess it doesn't take much to throw it off.  

I tapered the grip on this bow (first time) and that may have added to the difficulty as well.  It looks really good now though and to top it off, I'm getting a few folks asking if I will sell them a bow!  I'm having more fun giving them away at this time though (although I do have my eye on a power sander....)  :)

Offline Andrew Wesley

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Re: Limb twist
« Reply #4 on: March 21, 2009, 01:26:00 PM »
sometimes wood just has a weak side and will twist a little no matter what you do.

in my experience as long as your tiller is good and your string stay's within the width of your bow it should be fine.
one of my bows is practically a center shot because both limbs twisted over to the point where the string is on the edge of the left side. i shoot every day with it for 2 hours.. shoots great.

goodluck with more bow's.
~Andrew Wesley

Online Pat B

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Re: Limb twist
« Reply #5 on: March 21, 2009, 02:25:00 PM »
With your thumb and fore finger you can feel a difference in thickness that you might not be able to see. This is one of my tools when making wood bows and one that is free.
  Natural prop twist is different from twist due to uneven limb thickness. Uneven thickness can cause trouble because you are straining one side of the limb more than the other.
   I too have problems with uneven limb thickness when I use my bench vise because the out side is easier to access and see while the in side, against the bench, is a pain to get to and see. Once I get to floor tiller stage I use my shaving horse for tillering. I usually have to even up the limbs first.
Make the most of all that comes and the least of all that goes!
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Offline AKmud

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Re: Limb twist
« Reply #6 on: March 21, 2009, 04:56:00 PM »
I'm not familiar with a "shaving horse", could you describe it or do you have a pic?  Is it similar to just a saw horse?

Online Pat B

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Re: Limb twist
« Reply #7 on: March 21, 2009, 06:27:00 PM »
A shaving horse has a jaw that is foot operated to hold your bow or stave while you work on it. If I can find a pic I will post it.
Make the most of all that comes and the least of all that goes!
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